﻿using System;
using System.Collections.Generic;
using System.Text;

namespace DateConvert
{
    public class DateConvert
    {
        //定义星座数组
        private string[] ConstellationName = 
        { 
          "白羊座", "金牛座", "双子座", 
          "巨蟹座", "狮子座", "处女座", 
          "天秤座", "天蝎座", "射手座", 
          "摩羯座", "水瓶座", "双鱼座"
        };
        private DateTime m_Date;
        public DateTime Date
        {
            get { return m_Date; }
            set { m_Date = value; }
        }

        #region 类的构造函数
        public DateConvert()
        {
            Date = DateTime.Today;
        }
        public DateConvert(DateTime dt)
        {
            Date = dt.Date;
        }
        #endregion

        #region 计算指定日期的星座序号
        /// <summary>
        /// 计算指定日期的星座序号
        /// </summary>
        /// <param name="dt">指定的日期</param>
        /// <returns>星座序号</returns>
        public int GetConstellation(DateTime dt)
        {
            int Y, M, D;
            Y = dt.Year;
            M = dt.Month;
            D = dt.Day;
            Y = M * 100 + D;
            if (((Y >= 321) && (Y <= 419))) { return 0; }
            else if ((Y >= 420) && (Y <= 520)) { return 1; }
            else if ((Y >= 521) && (Y <= 620)) { return 2; }
            else if ((Y >= 621) && (Y <= 722)) { return 3; }
            else if ((Y >= 723) && (Y <= 822)) { return 4; }
            else if ((Y >= 823) && (Y <= 922)) { return 5; }
            else if ((Y >= 923) && (Y <= 1022)) { return 6; }
            else if ((Y >= 1023) && (Y <= 1121)) { return 7; }
            else if ((Y >= 1122) && (Y <= 1221)) { return 8; }
            else if ((Y >= 1222) || (Y <= 119)) { return 9; }
            else if ((Y >= 120) && (Y <= 218)) { return 10; }
            else if ((Y >= 219) && (Y <= 320)) { return 11; }
            else { return -1; };
        }
        #endregion

        #region 计算指定日期的星座名称
        /// <summary>
        /// 计算指定日期的星座名称
        /// </summary>
        /// <param name="dt">指定的日期</param>
        /// <returns>星座名</returns>
        public string GetConstellationName(DateTime dt)
        {
            int Constellation;
            Constellation = GetConstellation(dt);
            if ((Constellation >= 0) && (Constellation <= 11))
            { return ConstellationName[Constellation]; }
            else
            { return ""; };
        }
        #endregion

        //天干
        private static string[] TianGan =   { "甲", "乙", "丙", "丁", "戊", "己", "庚", "辛", "壬", "癸" };

        //地支
        private static string[] DiZhi =     { "子", "丑", "寅", "卯", "辰", "巳", "午", "未", "申", "酉", "戌", "亥" };

        //十二生肖
        private static string[] ShengXiao = { "鼠", "牛", "虎", "兔", "龙", "蛇", "马", "羊", "猴", "鸡", "狗", "猪" };

        //农历日期
        private static string[] DayName =   {"*","初一","初二","初三","初四","初五",
             "初六","初七","初八","初九","初十",
             "十一","十二","十三","十四","十五",
             "十六","十七","十八","十九","二十",
             "廿一","廿二","廿三","廿四","廿五",      
             "廿六","廿七","廿八","廿九","三十"};

        //农历月份
        private static string[] MonthName =  { "*", "正", "二", "三", "四", "五", "六", "七", "八", "九", "十", "冬", "腊" };

        //公历月计数天
        private static int[] MonthAdd =      { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };

        #region 农历数据
        /// <summary>
        /// 农历数据
        /// </summary>
        private static int[] LunarData =    {2635,333387,1701,1748,267701,694,2391,133423,1175,396438
            ,3402,3749,331177,1453,694,201326,2350,465197,3221,3402
            ,400202,2901,1386,267611,605,2349,137515,2709,464533,1738
            ,2901,330421,1242,2651,199255,1323,529706,3733,1706,398762
            ,2741,1206,267438,2647,1318,204070,3477,461653,1386,2413
            ,330077,1197,2637,268877,3365,531109,2900,2922,398042,2395
            ,1179,267415,2635,661067,1701,1748,398772,2742,2391,330031
            ,1175,1611,200010,3749,527717,1452,2742,332397,2350,3222
            ,268949,3402,3493,133973,1386,464219,605,2349,334123,2709
            ,2890,267946,2773,592565,1210,2651,395863,1323,2707,265877};
        #endregion

        #region 获取对应日期的农历及其他信息
        /// <summary>
        /// 获取对应日期的农历及其他信息
        /// </summary>
        /// <param name="dtDay">公历日期</param>
        /// <returns>农历信息</returns>
        public string GetLunarCalendar(DateTime dtDay)
        {
            string sYear = dtDay.Year.ToString();
            string sMonth = dtDay.Month.ToString();
            string sDay = dtDay.Day.ToString();
            int year;
            int month;
            int day;
            try
            {
                year = int.Parse(sYear);
                month = int.Parse(sMonth);
                day = int.Parse(sDay);
            }
            catch
            {
                year = DateTime.Now.Year;
                month = DateTime.Now.Month;
                day = DateTime.Now.Day;
            }
            int nTheDate;
            int nIsEnd;
            int k, m, n, nBit, i;
            string calendar = string.Empty;
            //计算到初始时间1921年2月8日的天数：1921-2-8(正月初一)
            nTheDate = (year - 1921) * 365 + (year - 1921) / 4 + day + MonthAdd[month - 1] - 38;
            if ((year % 4 == 0) && (month > 2))
                nTheDate += 1;
            //计算天干，地支，月，日
            nIsEnd = 0;
            m = 0;
            k = 0;
            n = 0;
            while (nIsEnd != 1)
            {
                if (LunarData[m] < 4095)
                    k = 11;
                else
                    k = 12;
                n = k;
                while (n >= 0)
                {
                    //获取LunarData[m]的第n个二进制位的值
                    nBit = LunarData[m];
                    for (i = 1; i < n + 1; i++)
                        nBit = nBit / 2;
                    nBit = nBit % 2;
                    if (nTheDate <= (29 + nBit))
                    {
                        nIsEnd = 1;
                        break;
                    }
                    nTheDate = nTheDate - 29 - nBit;
                    n = n - 1;
                }
                if (nIsEnd == 1)
                    break;
                m = m + 1;
            }
            year = 1921 + m;
            month = k - n + 1;
            day = nTheDate;
            //return year+"-"+month+"-"+day;
            #region 格式化日期显示为三月廿四
            if (k == 12)
            {
                if (month == LunarData[m] / 65536 + 1)
                    month = 1 - month;
                else if (month > LunarData[m] / 65536 + 1)
                    month = month - 1;
            }
            //生肖
            calendar = ShengXiao[(year - 4) % 60 % 12].ToString() + "年 ";
            //天干
            calendar += TianGan[(year - 4) % 60 % 10].ToString();
            //地支
            calendar += DiZhi[(year - 4) % 60 % 12].ToString() + " ";
            //农历月
            if (month < 1)
                calendar += "闰" + MonthName[-1 * month].ToString() + "月";
            else
                calendar += MonthName[month].ToString() + "月";
            //农历日
            calendar += DayName[day].ToString();
            return calendar;
            #endregion
        }

        public DateTime GetLunarCalendarDateTime(DateTime dtDay)
        {
            string sYear = dtDay.Year.ToString();
            string sMonth = dtDay.Month.ToString();
            string sDay = dtDay.Day.ToString();
            int year;
            int month;
            int day;
            try
            {
                year = int.Parse(sYear);
                month = int.Parse(sMonth);
                day = int.Parse(sDay);
            }
            catch
            {
                year = DateTime.Now.Year;
                month = DateTime.Now.Month;
                day = DateTime.Now.Day;
            }
            int nTheDate;
            int nIsEnd;
            int k, m, n, nBit, i;
            string calendar = string.Empty;
            //计算到初始时间1921年2月8日的天数：1921-2-8(正月初一)
            nTheDate = (year - 1921) * 365 + (year - 1921) / 4 + day + MonthAdd[month - 1] - 38;
            if ((year % 4 == 0) && (month > 2))
                nTheDate += 1;
            //计算天干，地支，月，日
            nIsEnd = 0;
            m = 0;
            k = 0;
            n = 0;
            while (nIsEnd != 1)
            {
                if (LunarData[m] < 4095)
                    k = 11;
                else
                    k = 12;
                n = k;
                while (n >= 0)
                {
                    //获取LunarData[m]的第n个二进制位的值
                    nBit = LunarData[m];
                    for (i = 1; i < n + 1; i++)
                        nBit = nBit / 2;
                    nBit = nBit % 2;
                    if (nTheDate <= (29 + nBit))
                    {
                        nIsEnd = 1;
                        break;
                    }
                    nTheDate = nTheDate - 29 - nBit;
                    n = n - 1;
                }
                if (nIsEnd == 1)
                    break;
                m = m + 1;
            }
            year = 1921 + m;
            month = k - n + 1;
            day = nTheDate;
            //return year+"-"+month+"-"+day;
            return Convert.ToDateTime(year.ToString()+"/"+month.ToString()+"/"+day.ToString());
        }
        #endregion
    }
}
